More Than A Substance: Ivory

Ivory is the hard white substance of which an elephant's tusks are made. Ivory can be used to make valuable things, such as jewellery, and in many places the sale of it has been forbidden to prevent people from illegally killing elephants to obtain the ivory from their tusks.
Ivory is also the colour of this substance, creamy white:
ivory shoes / an ivory dress
Ivory is also something made of this substance, especially a small figure of a person or a thing:
my collection of Chinese ivories
Tickle the ivories means to play the piano. The ivories is an informal word for teeth.
Ivory Soap is a type of soap used for washing the body and the face, usually sold in the US.
Ivory Tower is an imaginary place where it is thought very clever poeple (=intellectuals) hide to avoid the difficult realities of ordinary life:
university professors in their ivory towers